Some embodiments described herein relate generally to switch fabric systems, and, in particular, to methods and apparatus for standard protocol operations, administration and management/maintenance validation mechanism over a switch fabric system.
Some known switch fabric systems include an Equal Cost Multi Path (ECMP) mechanism that provides outgoing ECMP paths from, for example, a network or an Ethernet Packet Switching Fabric switching element, as members of a single multi-chassis link aggregation group (LAG) that originate on that switching element and which individual members terminate on different downstream switching elements. In such a known switch fabric system, the traffic (e.g., data packets) can get distributed across these ECMP paths based on a LAG load distribution mechanism in the hardware of the switch fabric system. The ECMP mechanism typically includes a hashing function that operates on a set of Packet Header fields, and optionally, other values programmed or computed in the hardware datapath. In a network or switch fabric using such an ECMP mechanism, any given flow can be load-balanced to one set of ECMP paths. For example, different types of data packets (e.g., Multicast, Unicast) can be routed through different paths within the network or switch fabric.
A typical operations, administration and management/maintenance (OAM) mechanism (e.g., validation process) interfacing with such a network or switch fabric, may fail to address such routing/forwarding techniques. For example, some known OAM mechanisms can determine the service-level connectivity for each L2 hop in a network or switch fabric determined by the usual flow of OAM protocol data units (PDUs) between hops with the assumption that all flow types take the same path between the hops as determined by STP (Spanning Tree Protocol) topology. Such a known OAM mechanism, however, can give a false positive or a false negative, resulting in incorrect interpretation and determination of service-level connectivity in the network or switch fabric as a whole.
In some known switch fabric systems, different data packet types can have different forwarding paths through the switch fabric. For example, ECMP functionality can apply to one traffic type, such as, for example, unicast traffic, while ECMP functionality may not apply to other traffic types, which may take linear forwarding path(s) through the switch fabric system. For example, multicast traffic can be forwarded on paths that are determined by a virtual local area network (VLAN) flooded path; such paths may not be an ECMP path.
Accordingly, a need exists for the ability to interface a known OAM mechanism with an OAM mechanism of an associated switch fabric system to validate possible ECMP paths, and other types of forwarding paths, through the switch fabric system between an external source device coupled to the switch fabric system and an external destination device coupled to the switch fabric system.